Extramedullary Plasmacytoma of the Head and Neck: A Retrospective Study

OBJECTIVE
Solitary extramedullary plasmacytomas (SEP) are rare plasma cell tumors that primarily occur in the head and neck regions. Due to their rarity, retrospective series can provide valuable insights into their clinical behavior and management, contributing to the refinement of treatment strategies. This study aimed to
report cases of SEPs in the head and neck region treated with radiotherapy (RT) over the last 20 years.
METHODS
Ten patients were enrolled in this study between January 2004 and January 2024. Their clinicopathological features and treatment protocols were recorded, and disease outcomes were analyzed.
RESULTS
The most common tumor site was the nasopharynx (n=5), followed by the nasal cavity (n=2). Nine of ten patients were initially treated with RT at the primary site. The median RT dose was 45.5 Gy (40–
58). Complete response (CR) was achieved in nine of 10 patients. The median survival duration was 74 months. The 5-year progression-free survival (PFS) rate was 85%. Only one patient developed a new bone plasmacytoma during the follow-up. No patient experienced transformation to multiple myeloma.
CONCLUSION
The prognosis of SEP is favorable, with rare recurrence, metastasis, and transformation to multiple myeloma. Further multicenter prospective studies are necessary to optimize management strategies for this rare entity.

Keywords: Extramedullary plasmacytoma; head and neck; nasal cavity; nasopharynx; solitary plasmacytoma.